Device for the automatic measurement of the length of yarn consumed in knitting machines

ABSTRACT

The invention relates to a method of and device for displaying the length of yarn used in making a given number of stitches on a knitting machine. With regard to the dimensions of the device microswitches are set to be activated at an interval of time during which the machine knits a selected number of stitches different from said given number. Electrical pulses are generated as the yarn is fed and are counted during the interval between activation of the microswitches. The length of yarn used in making the given number of stitches is displayed on the counter.

United States Patent 51 3,690,123

Delair et al. Sept. 12, 1972 [S4] DEVICE FOR THE AUTOMATIC 3,539,782 11/1970 Upshur ..66/125 UX MEASUREMENT OF THE LENGTH OF 3,550,400 12/1970 Peat et a1. ..66/125 UX Y ARN CONSUMED [N KNITTING 3,566,134 2/1971 Peat ..66/ 125 UX MACHINES FOREIGN PATENTS OR APPLICATIONS [72] m 5232 3 :33;; 21 2261 352 1,470,626 1/1967 France ..66/154 A Fran-Ce y 1,470,628 1 1967 France ..66/154 A [73] Assignee: Institut Textile de France, Bou- OTHER PUBLICATIONS logne, Fr The Hosiery Trade Journal, 3/68, Vol. 75, No. 891, [22] Filed: March 9, 1970 PP- 8,91 & 92 g [21] Appl. No.: 17,491 Primary Examiner-Wm. Carter Reynolds Attorney-Marshall Yeasting [30] Foreign Application Pr ority Data ABSTRACT March 17, 1969 France ..6907568 The invention relates to a method of and device for displaying the length of yarn used in making a given g number of stitches on a knitting machine. With regard [58] Fie'ld 'g 66/l25 1 154A 132 126 to the dimensions of the device microswitches are set 8 to be activated at an interval of time during which the machine knits a selected number of stitches different from said given number. Electrical pulses are [56] References cued generated as the yarn is fed and are counted during UNITED STATES PATENTS the interval between activation of the microswitches. The length of yarn used in making the given number 1;; w l l g of stitches is displayed on the counter. e er 3,408,500 10/ 1968 Carr ..66/ 1 R X 9 Claims, 3 Drawing figures 5 1 I 5 l6 V .I

J 1, I6 I v ,9 i 17 I DEVICE FOR THE AUTOMATIC MEASUREMENT OF THE LENGTH OF YARN CONSUMED IN KNITTING MACHINES The present invention relates to a method of and a device for the automatic measurement of the length of yarn consumed in knitting machines, particularly hosiery knitting machines.

The length ofyarn used in knitting machines can be estimated by measuring yarn withdrawal velocity from the bobbin with a tachometer, or by measuring the yarn used by the machine during one or more revolutions of the machine.

The second method is more common, particularly when a positive feeder, that is a means supplying to the machine a length of yarn per revolution which is equal to its circumference,is used. The number of revolutions of the positive feeder is a measure of the consumption of yarn for a given number of machine revolutions.

Known devices for this method count the number of revolutions of the positive feeder which occur during a given number of revolutions of the machine in the case of a circular knitting machine for example, or on one row in two in the case of knitting machines of the Cotton type.

The main disadvantages of these devices is that the integrator does not directly give the length of yarn used per stitch.

According to one aspect of the present invention there is provided a method of measuring the length of yarn used in a given number of stitches on a knitting machine, said method including the steps of generating a number of electrical pulses said number being related to the length of yarn passed to the machine, and supplying said pulses to a counter while a preselected number of stitches are made by the machine, said preselected number being different from said given number, whereby said counter gives a direct reading of the length of yarn used in said given number of stitches.

According to a second aspect of the present invention there is provided a device for measuring the length of yarn used in a given number of stitches by a knitting machine including a feeder rotated in accordance with the movement of the fed yarn, a pulse generator for generating a number of electrical pulses in accordance with the length of yarn fed, a counter connected thereto via an output element, a first microswitch actuatable on operation of the machine to pass a pulse via a first circuit to the output element and a preselection counter and a second microswitch actuatable on operation of the machine and located in a second circuit between the preselection counter and the output element, whereby a pulse from the first circuit causes the output element to pass pulses to the counter and a pulse from the second circuit causes the output ele ment to cease passing pulses to the counter.

In considering the invention it should be noted that for a given operation of measuring using as data the number of revolutions of a feeder and the number of stitches made, the following equation holds:

Length in mm. of yarn for 100 stitches, L (B X n)/N X 100 1 where:

B circumference of the feeder in mm.;

n number of revolutions effected by the feeder during counting;

N number of stitches knitted during the measurement or metering operation.

Therefore, if the numerical ratio between the latter number and the circumference of the positive feeder is known the number of stitches made during a measuring operation can be controlled to give, on the counter, a figure corresponding to the length of yarn used in, for

' instance, 100 stitches.

Thus, if, for instance, the number N representing the stitches knitted during the measurement has a numerical value equal to 10 times that of the circumference of the positive feeder, equation l becomes:

If there are, for instance, ten pulses from the pick-up for each revolution of the feeder,then the number of pulses counted is the length of yarn used in stitches.

In the case of circular knitting machines, the number of stitches knitted per revolution is not identical for each of the machines utilized. For each type of machine, the measurement will therefore have to be made on at least one single revolution plus or minus a part of a revolution, so that the number of stitches knitted during the measurement is equal to N.

In order that the invention may be more clearly understood, the following description is given, merely by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a general diagrammatic view of a device according to the invention;

FIGS. 2a and 2b are diagrammatic views of the positions of the microswitches in the device relative to the knitting machine.

As illustrated in FIG. 1, the device includes a yarn feeder l to the knitting machine, having a disc 2 attached thereto. The disc 2 has a given number of sectors which are alternately clear or reflective and dark or non-reflective. Non-reflective sectors are obtained by depositing, for example, matt black paint at the appropriate places. The disc 2 is illuminated by a small lamp (not shown) incorporated in a pick-up 3 which also contains a photoelectric cell to pick up light reflected from the disc 2. When a non-reflective sector is illuminated little light is reflected compared to the case where a reflective area is illuminated, so that a succession of electrical pulses are issued by the photoelectric cell. The pulses from the pick-up 3 are amplified and shaped in the circuit 4 and are then directed to an integrator 6 via an output element 5. The output element does not pass pulses when it is activated.

A microswitch 7 is closable by a means such as a dog 8 rotating on the knitting machine (FIGS. 2a and 2b), rotatable once with each circuit or row knitted. One of the contact studs of the microswitch is connected to a positive voltage source, and the switch is adapted to supply an electrical pulse each time the dog actuates it. The pulse is shaped in a circuit 9 and fed both to a preselection counter 10 and to an intermediate element 1 l which deactivates the output element 5.

A two way switch 12 is connected to the output of the preselection counter 10. In one of its positions the switch 12 connects the preselection counter 10 to an intermediate element 13, for example a thyristor, which is connected to the input of the output element 5 via a diode 14. The purpose of the intermediate element is to activate or deactivate the output element 5.

In its second position the two way switch 12 connects the preselection counter to a further intermediate element 15 which is connected to a microswitch 16. The microswitch 16 is also adapted to be actuated by the dog 8 on the knitting machine. The intermediate element 15 is also connected to the positive terminal of a voltage source. The microswitch 16, when closed, transmits a pulse to a shaper circuit 17 connected in series to a control element 18, for example a flip-flop, the output terminal of which is connected via a diode 19 to the output element 5. The preselection counter 10 may be set to transmit the first or a subsequent pulse received from the shaper 9. If it does not pass a pulse then no pulse flows from intermediate element 15, which may be a thyristor, when switch 16 is closed. The counters 6 and 10 may be reset by hand at the end of each counting operation in accordance with conventional practice.

The device operates as follows with respect to circular knitting machines. In this description it is assumed that B, the circumference of the feeder l, is numerically equal to 132 units of length. If therefore N, the number of stitches measured is again 10 times this number, it is necessary to carry out a measurement of the yarn used in 1,320 stitches. This will give a value of the yarn used per 100 stitches (in terms of the same length units as B is measured in) of 10n, where n is the number of revolutions of the feeder during measurement (equation 2). Clearly, therefore, if the disc 2 to the feeder has twenty sectors, half reflective and half not so, it will deliver ten pulses to the photoelectric cell per revolution. Since the circumference of the feeder 1 is 132 units of length, it follows that the length of yarn fed per pulse is 13.2 units. In order that the number of pulses passed during measurement may be a direct indication of the number of units of length of yarn used per 100 stitches, the measurement is carried out over a number of stitches equal to 100 times the number of units of length of yarn fed per pulse, i.e. 1,320 stitches. The number of pulses passed to the integrator 6 during the making of 1,320 stitches is, in these circumstances, equal to the length of yarn used in making 100 stitches. Under these conditions, if the knitting machine knits more than 1,320 stitches per revolution the arrangement of the microswitches 7, 16 should be as shown in FIG. 2a.

In operation, a no-load of open circuit setting is first effected, i.e., the intermediate element 15, the shaper circuit 17 and the control element 18 are put out of circuit, and the preselection counter 10 is connected to the intermediate element 13 by means of the switch 12. It is the object of this first setting to enable the respective positions of the microswitches 7 and 16 to be set by hand, such that the machine knits 1,320 stitches between the time the dog 8 contacts the switch 7 and the time when it contacts the switch 16. Such positions of the microswitches 7 and 16 having been established, the position of the two way switch 12 is reversed so that the preselection counter 10, on which the numeral 1 is displayed, will pass the first pulse from shaper 9 to the intermediate element 15.

Before the dog 8 energizes the microswitch 7, the output element 5 is activated and the pick-up 3 pulses do not pass. When the dog 8 energizes the microswitch 7, the pulse produced and converted in the shaper circuit 9 is fed simultaneously to the preselection counter 10 and the intermediate element 11 which deactivates the output element 5, the consequence of this being to permit passage of the pulses derived from the pick-up 3, which are counted at the integrating counter 6.

When the dog 8 energizes the microswitch l6, i.e., when the knitting machine has knitted exactly 1,320 stitches, the output element 5 is re-energized, and no further pulses from the amplifier and the shaper circuit 4 reach the counter 6. The number displayed at the counter 6, in this case, directly indicates the length of yarn consumed by stitches.

If, as opposed to the above situation the knitting machine knits less than 1,320 stitches per revolution, but more than 660, for example 700 stitches, a different arrangement of the switches must be used. More than one revolution of the machine must occur in the counting period. On the first revolution 700 stitches will be made, and the time for a further 620 stitches must be added to bring the total to 1,320. As shown in FIG. 2b the microswitches 7 and 16 are positioned so that the machine knits 620 stitches while the dog moves between the switches on the second revolution. Thus, on the first revolution the dog energizes switch 7 with the result that the output element 5 is deactivated and pulses from the pick-up 3 pass to the counter 6. The dog does not cause the switch 16 to generate a pulse on the first revolution, but on the second revolution it energizes the microswitch 16 which stops the measurement. Thus, the counter 6 shows the length of yarn consumed for 100 stitches. The preselection counter 10 is in this case set to 2 in order that the second pulse from shaper 9 passes to element 15, so that the counter can proceed for more than one revolution.

It will thus be clear that, with this method and device, it is possible to directly ascertain the length of yarn used up per stitch, whatever the type of feeder with which the knitting machine is equipped. If the knitting machine knits 400 stitches per revolution, the measu rement should be effected on three revolutions plus stitches.

The device may be fitted on a n0n-circular knitting machine of the Cotton type, wherein the feeder effects one linear travel per knitted row, the measurement then being effected either on n/2 successive rows or on n rows of the same direction (n being the number displayed on the preselection counter).

It is important to point out that the present apparatus may be used on knitting machines equipped with feeders of a type differing from that as shown, or on knitting machines not equipped with feeders. The pickup means will then be by a small wheel or roller of known perimeter, entrained by the yarn, the rotation thereof being measured by the process described hereabove.

The number N of stitches on which the measurement is effected (in this case as described 1,320) is, as has been shown, linked with the perimeter of the feeder or of the metering wheel. If the said perimeter should vary, the number N will be required to vary accordingly.

We claim:

1. A device for measuring the length of yarn used in a given number of stitches by a knitting machine, said device comprising in combination:

a. a feeder rotated by said yarn b. a-pulse generator for generating pulses as said feeder rotates c. an output element connected to said pulse generator d. a counter connected to said output element e. first and second microswitches actuatable on operation of the machine f. a first circuit between said first microswitch and said output element g. a preselection counter connected to said first microswitch, and adapted selectively to pass a selected pulse h. a second circuit including said second microswitch connecting said preselection counter to said output element whereby a pulse from said first circuit to said output element causes said output element to pass pulses from said pulse generator to said counter and a pulse from said second circuit to said output element causes said output element to cease to pass pulses from said pulse generator to said counter.

2. A device as claimed in claim 1 further comprising a disc attached to said feeder, and alternate reflective and non-reflective segments to said disc.

3. A device as claimed in claim 2 wherein said pulse generator comprises a light source and a photocell adjacent said disc to pick up light reflections from said reflective segments of said disc.

4. A device as claimed in claim 1 further comprising a member to said machine rotatable with said machine, and a dog on said member to actuate said microswitches.

5. A device as claimed in claim 4 wherein said microswitches are adjustable to be actuated by said dog at different intervals.

6. A device as claimed in claim 1 further comprising a third circuit including an intermediate element and a diode connected to said output element and a two way switch connected to said preselection counter and switchable to connect said preselection counter respectively a. to said second circuit or b. to said third circuit.

7. A device as claimed in claim 6 wherein said intermediate element is a thyristor.

8. A device as claimed in claim 1 further comprising a function selector and a diode in said first circuit.

9. A device as claimed in claim 1 wherein said second circuit additionally comprises an intermediate element energizable by a pulse from said preselection counter, and a control element and a diode. 

1. A device for measuring the length of yarn used in a given number of stitches by a knitting machine, said device comprising in combination: a. a feeder rotated by said yarn b. a pulse generator for generating pulses as said feeder rotates c. an output element connected to said pulse generator d. a counter connected to said output element e. first and second microswitches actuatable on operation of the machine f. a first circuit between said first microswitch and said output element g. a preselection counter connected to said first microswitch, and adapted selectively to pass a selected pulse h. a second circuit including said second microswitch connecting said preselection counter to said output element whereby a pulse from said first circuit to said output element causes said output element to pass pulses from said pulse generator to said counter and a pulse from said second circuit to said output element causes said output element to cease to pass pulses from said pulse generator to said counter.
 2. A device as claimed in claim 1 further comprising a disc attached to said feeder, and alternate reflective and non-reflective segments to saId disc.
 3. A device as claimed in claim 2 wherein said pulse generator comprises a light source and a photocell adjacent said disc to pick up light reflections from said reflective segments of said disc.
 4. A device as claimed in claim 1 further comprising a member to said machine rotatable with said machine, and a dog on said member to actuate said microswitches.
 5. A device as claimed in claim 4 wherein said microswitches are adjustable to be actuated by said dog at different intervals.
 6. A device as claimed in claim 1 further comprising a third circuit including an intermediate element and a diode connected to said output element and a two way switch connected to said preselection counter and switchable to connect said preselection counter respectively a. to said second circuit or b. to said third circuit.
 7. A device as claimed in claim 6 wherein said intermediate element is a thyristor.
 8. A device as claimed in claim 1 further comprising a function selector and a diode in said first circuit.
 9. A device as claimed in claim 1 wherein said second circuit additionally comprises an intermediate element energizable by a pulse from said preselection counter, and a control element and a diode. 